D!ZONE was a series of CD-ROMs produced around 1995 by WizardWorks, Inc., containing batches of Doom add-ons created by fans, harvested from bulletin boards, Compuserve/AOL walled garden file stores, etc.
D!ZONE Gold was the last release in the series.
More information: http://doomwiki.org/wiki/D!ZONE
And: http://redump.org/disc/4500/